Method of preparing a radioactive yttrium phosphate particle suspension

ABSTRACT

A method of preparing a radioactive yttrium phosphate particle suspension.

FIELD AND BACKGROUND OF THE INVENTION

A method of preparing a radioactive yttrium phosphate particle suspension for the treatment of tumors including solid tumors.

The patents and publications referred to herein are provided herewith in an Information Disclosure Statement in accordance with 37 CFR 1.97.

SUMMARY OF THE INVENTION

The method claimed is the preparation of radioactive yttrium phosphate particles of a size preferred for interstitial application in solid tumors.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other features and advantages of the present invention will become more readily appreciated as the same become better understood by reference to the following detailed description of the preferred embodiment of the invention when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates particle size determined through the claimed process with pH of 7.35 yielding particle median size of 0.2450 um. And FIG. 2 with pH 7.4 and median particle size of 0.1844 um with particles in each of FIG. 1 and FIG. 2 providing interstitial effectiveness for cell space application.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above description and figures. The exemplary embodiment was chosen and described in order to best explain the principles of the present invention and its practical application for purposes of enabling others who are skilled in the art and making of the product to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated.

DETAILED DESCRIPTION OF THE INVENTION

A method of preparing a radioactive yttrium salt particle suspension comprising multiple steps comprising: using a hydrothermal process wherein a solution of soluble yttrium salt, from the group of yttrium chloride, yttrium nitrate, yttrium sulfate, and yttrium bromide. is combined with a solution of sodium phosphate having a stoichiometric excess of phosphate and pH when combined in the range of 1.5 to 8.

Combining the solutions with continuous stirring and rapidly heating in a closed vessel to 150° C. and held for 1 to 10 hours to yield greater than 99.99% conversion of soluble yttrium to insoluble YPO₄ and to achieve the desired particle size distribution and;

Creating the desired particle size distribution of YPO₄ particles suspended in buffered saline at neutral pH suitable for direct injection into human or animal tissue.

The radioactive particle suspension wherein the particle size is less than 2 um.

The radioactive particle suspension comprised of at least 90 percent of the total particle volume consisting of particles in the range of 0.1 um to 2 um.

And further comprising: wherein the starting concentration of soluble yttrium in the combined solution is in the range of 0.5 to 3.0 mole/liter and the stoichiometric excess of phosphate ranges from 10 to 100%.

And further, comprising: the starting concentration of soluble yttrium in the combined solution is 0.08 moles/liter and the stoichiometric excess of phosphate is 25%.

The method further comprising: the particle suspension formed by preparing the particle precursor solution, mixing and heating to form the YPO₄ particles by controlled precipitation followed by post-processing the particles to achieve a suspension of YPO₄ particles in phosphate buffered saline solution at neutral pH suitable for injection into human or animal tissue.

The method further comprising: the particle suspension wherein the post processing consists of rinsing the particles 3 times with sterile phosphate buffered saline (PBS) solution and removing or adding PBS to achieve the final desired volume.

The method further comprising: the particle suspension wherein the post processing consists of adjusting the pH of the final solution with sodium hydroxide then removing excess solution or adding sterile PBS to achieve the final desired volume.

The method further comprising: the particle suspension wherein the yttrium phosphate particles are radioactive to serve as distributed sources of therapeutic radiation for treating cancerous tumors and other diseases and: making the particles radioactive by adding a small mass of soluble radioactive isotope to the particle precursor solution that becomes homogeneously incorporated into the insoluble yttrium phosphate particle matrix.

The method further comprising; the yttrium phosphate particle suspension wherein the particle concentration is in the range of 40 mg/ml to 125 mg/ml to facilitate imaging by x-ray computed tomography after being combined in a ratio of 1 to 4 by volume with biocompatible hydrogel or other suitable liquid carrier solution for injection into human or animal tissue. 

1. The method of preparation of yttrium phosphate particles comprising: step 1—preparing reagents: step 1.1. weighing out a non-radioactive (i.e. Y-89) yttrium salt from the group of yttrium chloride, yttrium nitrate, yttrium sulfate, and yttrium bromide and transferring quantitatively to a volumetric flask; adding deionized water; agitating to mix completely; and step 1.2 drawing up the ⁸⁹Y⁺³ solution from the volumetric flask into a syringe and pushing the solution through a filter and collecting the solution in a sterile container; and step 1.3 preparing and filtering 0.15 M Na₂HPO₄ and 0.05M HCl reagents; storing the reagents at room temperature; and step 2—preparing a radioactive ⁹⁰YCl₃ solution: adding to a source vial containing ⁹⁰YCl₃ a sufficient volume of 0.05 NI HCl, to achieve recovery of the desired quantity of radioactive material from the source vial; and step
 3. radioactive (⁹⁰Y+⁸⁹Y) PO₄ synthesis procedure; step 3.1. adding H₂O to the to a microwave reaction vial with a sterile magnetic stir bar; and placing the reaction vessel on a stir plate; and with continuous stirring step 3.2. adding 0.15 M Na₂HPO₄; and step 3.3. adding ⁸⁹Y⁺³ solution; and step 3.4. adding ⁹⁰Y in 0.05 M HCl from a Source vial; and step 3.5, recording the final pH and step 3.6. transferring the vial to a microwave reactor; and step 3.7 setting the reaction temperature to a temperature in the range of 110° C. to 160° C. and reaction time to between one hour and 20 hours and starting the reactor; and step 4 final steps: step 4.1. placing the microwave vial with the particles in a centrifuge, subjecting the particles to centrifugation; and step 4.2. remove the supernatant liquid and replace with sterile phosphate buffered saline, and repeating steps 4.1 and 4.2 two additional times; and step 4.3. removing excess supernatant liquid from the vial; and step 4.4. labeling the vial with identity, lot number, and date of manufacture.
 2. The method of preparation of yttrium phosphate particles depending from claim 1 and further comprising: step 1.1. 1.0 M ⁸⁹YCl₃: weighing out nonradioactive (i.e., Y-89) YCl₃.6H₂0 and transferring quantitatively to a volumetric flask; adding deionized water to the volumetric flask; agitating to mix completely; and step 1.2 drawing up the 1.0 M ⁸⁹YCl₃ solution into a syringe and pushing the solution through a filter and collecting the solution in a sterile container; and step
 3. radioactive (⁹⁰Y+⁸⁹Y)P0₄ synthesis procedure; step 3.1. adding 1.0 ml of H₂0 to the to a microwave reaction vial with a sterile magnetic stir bar; and placing the reaction vessel on a stir plate; and with continuous stirring step 3.2. adding 2.67 ml of 0.15 M Na₂HPO₄; and step 3.3. adding 0.32 ml of ⁸⁹YCl₃ solution; and step 3.4, adding up to 0.05 ml of ⁹⁰Y in 0.05 M HCl from a Source vial; and step 3.5. recording the final pH and step 3.6. transferring the vial to a microwave reactor; and step 3.7 setting the reaction temperature to 150° C. and reaction time to one hour and starting the reactor; and step 4 final steps: step
 4. L adjusting the pH of the product solution with 1.0 N NaOH to pH range of 1.5 to 8; and step 4.3. removing supernatant leaving 01.0 mL in the vial for each scheduled tumor treatment.
 3. The method of preparation of a volume of yttrium phosphate particles depending from claim 2 and further comprising: step 1.1. 1.0 M ⁸⁹YCl₃: weighing out non-radioactive (i.e., Y-89) YCl₃.6H₂0 for a single scheduled tumor treatment, to the nearest 0.01 g) 0.03±0.15 g and transferring quantitatively to a 10 mL volumetric flask; adding 10 mL deionized water to the 10 mL mark; agitating to mix completely; and step 1.2 drawing up ˜8-10 mL of 1.0 M ⁸⁹YCl₃ into a syringe and pushing the solution through a filter and collecting the solution in a sterile container; and step 1.3 preparing and filtering 0.15 M Na₂HPO₄ and 0.05 M HCl reagents; and step 4 final steps: step 4.1. adjusting the pH of the product solution with 1.0 N NaOH to pH range of 7 to 8; and step 4.3. removing supernatant leaving 1.0 mL in the vial for each scheduled tumor treatment.
 4. A method of preparing a radioactive yttrium phosphate particle suspension comprising: using a hydrothermal process where in a solution of yttrium salts from the group of yttrium chloride, yttrium nitrate, yttrium sulfate, and yttrium bromide is combined with a solution of sodium phosphate having a stoichiometric excess of phosphate and a pH when combined in the range of 1.5 to 8; combining the solutions with continuous stirring and rapidly heating in a closed vessel to the range of 110° C. to 160° C. and held for 1 to 20 hours to yield greater than 99.99% conversion of soluble yttrium to insoluble YPO₄ and to achieve the desired particle size distribution and; creating the desired particle size distribution of YPO₄ particles suspended in buffered saline at neutral pH suitable for direct injection into human or animal tissue.
 5. The method depending from claim 4 further comprising: the radioactive particle suspension wherein the particle size is less than 2 um.
 6. The method depending from claim 5 further comprising: the radioactive particle suspension comprised of at least 90 percent of the total particle volume consisting of particles in the range of 0.1 um to 2 um.
 7. The method depending from claim 6 and further comprising: wherein the starting concentration of soluble yttrium in the combined solution is in the range of 0.5 to 3.0 mole/liter and the stoichiometric excess of phosphate ranges from 10 to 100%.
 8. The method depending from claim 6 and further comprising: the starting concentration of soluble yttrium in the combined solution is 0.08 moles/liter and the stoichiometric excess of phosphate is 25%.
 9. The method of claim 4 further comprising: the particle suspension formed by preparing the particle precursor solution of claim 4, mixing and heating to form the YPO₄ particles by controlled precipitation followed by post-processing the particles to achieve a suspension of YPO₄ particles in phosphate buffered saline solution at neutral pH suitable for injection into human or animal tissue.
 10. The method of claim 9 further comprising: the particle suspension wherein the post processing consists of rinsing the particles 3 times with sterile phosphate buffered saline (PBS) solution and removing or adding PBS to achieve the final desired volume.
 11. The method of claim 9 further comprising: the particle suspension wherein the post processing consists of adjusting the pH of the final solution with sodium hydroxide then removing excess solution or adding sterile PBS to achieve the final desired volume.
 12. The method of claim 4 further comprising: the particle suspension of claim 4 wherein the yttrium phosphate particles are radioactive to serve as distributed sources of therapeutic radiation for treating cancerous tumors and other diseases; and making the particles radioactive by adding a small mass of soluble radioactive isotope to the particle precursor solution of claim 4 that becomes homogeneously incorporated into the insoluble yttrium phosphate particle matrix.
 13. The method of claim 4 further comprising; the yttrium phosphate particle suspension of claim 4 wherein the particle concentration is in the range of 40 mg/ml to 125 mg/ml to facilitate imaging by x-ray computed tomography after being combined in a ratio of 1 to 4 by volume with biocompatible hydrogel or other suitable liquid carrier solution and injection into human or animal tissue and: where the solution of sodium phosphate having a stoichiometric excess of phosphate and a pH in the range of 7 to
 8. 